Process for beneficiation of asphaltite material



P. E. MCGARRY Filed Jan. 6, 1955 March 7, 1961 PRocEss FOR BENEFICIATIONoF ASPHALTITE MATERIAL x Fusil, w

United States Patent() PROCESS FOR BENEFICIATION OF ASPHALTITE- MATERIALFiled Jan. 6, 1955, Ser. No. 480,289

9 Claims. (Cl. 209-166) This invention relates to the benetication ofuraniumbearing asphaltite ore. More particularly, it relates to thebenecation of rock impregnated with bituminous material bearing uraniumcomponents. Still more particularly, it relates to a flotation processfor dolomitic formations imprognated with uranium-bearing bitumens.

Asphaltite or bituminous rocks such as gilsonite, grahamite, wurtzilite,etc., are mined in various sections of the United States. VIn thewestern states there are numerous occurrences of dolomite formationscontaining uranium-bearing asphaltite material. The percentage ofasphaltite material present in these ores is relatively small, generallyless than about 10% and usually being .of the order of about 1% to about5%. The uranium analyzed as U3O8 is present in quantities generally ofthe order of about 0.01% to about 0.06% by weight of the ore. Chemicalrecovery methods are not economically feasible for use on such'low gradeuranium ore materials.

It is an object of this invention to provide a relatively inexpensivemethod of recovering the bituminous material and the uranium compoundsassociated therewith in a concentrated form.

It is still another object of this invention to provide an economicalfeasible method for preparation of an asphaltite concentrate useful as afeed material for chemical extraction processes for the recovery ofuranium.

These and other objects will be apparent to those skilled in the artfrom the following description and a'ccompanying drawing which is adiagrammatic sketch of a beneciation process in accordance with thepresent invention.

Now it has been discovered that the asphaltite ore rnaterials can besubjected to ore otation operations in the absence of collectors and thegangue depressed soV that a beneciated uranium-bearing bitumenconcentrate may be recovered.

The method as applied to dolomitic ore such as is foundV in New Mexicoand Utah, for example a limestone ore impregnated with between about 1%and about 2% of bitumen, consists of crushing or grinding the ore toliberate the bitumen fraction, recovering an 'aqueous pulp, aerating thepulp with or without frother material present; or alternatively firstaerating the pulp without frother present followed by treatment in thepresence of frother material, conditioning the flotation concentratewith dispersant for nullifying the effect of contaminants on thelimestone gangue, and subjecting the treated concentrate to aeration andagitation to separate limestone gangue from the final bitumen 'otation'concentrate. By frother material is meant a foam forming agent such asthe alcohol, isobutyl carbinol or foam forming agent plus frothmodifiers such as the frother pine oil plus the modifier such as fueloil.

Run of the mine ore as received is subjected to jaw crushing, conecrushing, yrod milling and sizing operations to produce a pulp havingparticles of a size generally smaller than about l mesh or about 20mesh.

N Alinatented Mar. 7, 1961 The mesh of grind Vfor sizing may shiftsomewhat depending upon the mesh size for liberation of the particlemixture, but the mesh of grind will seldom be coarser than above 4 meshor finer than about 100 mesh.

The pulp of, for example, -20 mesh size particles is dewatered to theproper pulp density for conditioning, if it is to be reagentize'd, insuitable equipment such as Dorr classifiers, cyclones, Akinsclassifiers, and the like. Pulp is concentrated to a solids contentgenerally in the range between about and about 75% solids by weight, andpreferably to between about and about by weight.

if the pulp is to be subjected to agitation and aeration withoutreagentizing, then the dilute pulp is Vpassed to flotation apparatus orconcentrated pulp is diluted to a solids content of about 20% to about40% by weight, preferably to between about 25% and about 30% by weight.Generally, it is desirable for this flotation operation that the slurry`be at or near neutrality, preferably at a p-H in the range betweenabout 5 and about 9.

-If a reagentized type flotation is to be effected, the frother materialmay be added to the dilute pulp, but preferably is added to a thickpulp. Effective frothers for this operation are hydrocarbons, such asfuel oil; alcohols, such as straight chain aliphatic alcohols of betweenyabout 4 and about 8 carbon atoms, for example, isobutyl carbinol hexylalcohol and the like; and cyclic alcohols such as the terpineols, morecommonly used in an impure form known as pine oil. Such frothingmaterials may be used individually or in mixtures, and are known in thetrade by their chemical names or sold under tradenames such as AmericanCyanamids Aerofroth mixtures, Sharples Pentasol 23,V and the like.

Flotation of the bituminous material may be carried out in suitableapparatus such as Fagergren or Denver Y flotation machines, orequivalent apparatus arranged so as to have one or more sepa-rationstages.

From the flotation operation wherein the slurry is agitated and aeratedthere is recovered a bituminous concenv trate and a basically dolomitetail. The tail product usually is discarded. The concentrate from thefirst or rougher flotation is usually subjected toa cleaner or a secondotation operation with or without change in the reagent conditions.`Concentrate from this'preliminary separationV operation is subjected totreatment with dispersants, one' of whose purposes'isV to clean thegangue material suring tank, Vthe Vslurry is partially freed ofdispers-ants by Y dewatering and washing operations.` This rougher or fcleaner concentrate is subjected to one or more stages of recleaneroperation to produce a final flotation concentrate. VFeed to thisrecleaner operation consists generally of concentrated slurry :adjustedto la solids content ofthe order o-f about 20% to about 30% solids. Tailproducts from the ore cleaner operation rnay be discarded; orif highenough in `U3O8 content the tail product may be re-" cycled, forexample, to a prior-l'lotatiorrstage, for example, to the rougher. t Theinvention will be more clearly understood from thetollowingexample whichis given by" way of illustration and without any intention that the in-1vention be limited thereto. l

Example I Percent by Weight 96 Dolomite Asphaltite 1.5 to 2 Quartz 1Mica 1 UaOa content 0.037

This ore was crushed, ground and size to produce a flotation feedapproximately 100% of which passed through a 20 mesh standard screen.The -20 mesh material was mixed with water to produce a slurry ofapproximately 65% by weight solids content. The slurry was divided intofour equal portions, A, B, C and D. Portion A after agitation in aconditioning tank for five minutes was diluted to a solids content ofapproximately 30% and introduced into aDenver subaeration flotationmachine. For each 1000 parts by weight of dry solids fed to theflotation yoperation there was recovered 14 parts by weight of drysolids in the overflow or concentrate product. This concentrate analyzed0.76% U3O8, which represents a recovery of approximately 30% of the U3O8present in the feed.

Example Il Portion B from Example I Was agitated in the sameconditioning tank for 5 minutes after there was added to the slurry 0.04pound per ton of solids of pine oil. After conditioning, the conditionedconcentrate was introduced into the same Denver subaeration flotationmachine. For each 1000 parts by weight of dry solids feed there wasrecovered as a concentrate or overflow product 34 parts by weight ofsolids. This concentrate contains 0.67% UaOS, which represents arecovery of approximately 65% of thc U3O3 present in the feed.

Example III Portion C from Example I was introduced into theconditioning tank and 0.07 pound per ton of dry solids of pine oil and0.6 pound per ton of Bunker C fuel oil were added. After agitation for 5minutes, the conditioned slurry was diluted to a solids content ofapproximately 30% and introduced into the same Denver subaerationflotation machine. For each 1000 parts by weight Iof dry solids fed tothe machine there was recovered 68 parts by weight of dry solids as aconcentrate. This concentrate contained 0.44% U3O8, which represents a'recovery of approximately 86% of the USOS in the feed. This concentratewas introduced into the conditioning tank of Example I and 5 pounds ofsodium hexametaphosphate added per ton of dry solids. After 5 minutesagitation in the conditioning tank the scrubbed slurry was dewatered andwashed in an Akins` type classifier. The washed solids were slurriedwith water to have a solids content of approximately 30%, and the slurrywas then floated in the same Denver subaeration flotation machine. Foreach 1000 parts by weight of dry solids fed to the initial flotationoperation there was recovered l0 parts by weight of dry solids. Thisfinal concentrate contained 2.3% USOS, which represents a recovery ofapproximately 70% of the UaOS in the original feed. By drying andigniting this otation concentrate in a muffle furnace a product assayingapproximately 22% U3O8 was produced.

.Having thus described the invention what I claim is:

1. A method for the beneficiation of uranium-bearing asphaltite orewhich comprises comminuting the ore to liberation of the bituminousconstituents, converting the liberated ore to an aqueous pulp andagitatiug and aerating the pulp in the absence of a collector to effectflotation of a bituminous concentrate, scrubbing the concentrate inslurry form with dispersants for bituminous material, washing thescrubbed slurry free of contaminants and dispersants and aeratng andagitating the scrubbed concentrate in the absence of a collector toeffect flotation and to recover a second bituminous concentratecontaining the uranimum constituents.

2. A method for the beneficiation of uranium-bearing asphaltite orewhich comprises comminuting the ore to liberation of the bituminousconstituents, converting the liberated ore to an aqueous pulp,conditioning the aqueous pulp in the absence of a collector with frothcrmaterial, agitating and aerating the pulp to effect flotation of abituminous concentrate, scrubbing the concentrate in slurry form withdispersants for bituminous material, washing the scrubbed slurry free ofcontaminants and dispersants and aerating and agitating the scrubbedconcentrate in the absence of a collector to effect flotation and torecover a second bituminous concentrate containing the uraniumconstituents.

3. A method for the beneficiation of uranium-bearing asphaltite orewhich comprises comminuting the ore to liberation of the bituminousconstituents, converting the liberated ore to an aqueous pulp andagitating and aerating the pulp in the absence of a collector at s. pHin the range between about 5 and about 9 to effect otation of abituminous concentrate, scrubbing the concentrate in slurry form withdispersants for bituminous material, Washing theA scrubbed slurry freeof contaminants and dispersants and aerating and agitating the scrubbedconcentrate in the absence of a collector to effect flotation and torecover a second bituminous concentrate contain ing' the uraniumconstituents.

4. A method for the beneficiation of uranium-bearing asphaltiteimpregnated limestone which comprises comminuting the ore to liberationof the bituminous constituents, converting the liberated ore to anaqueous pulp, conditioning the aqueous pulp with frother material,agitating and aerating the pulp in the absence of a collector to effectflotation of bituminous concentrate, scrubbing the concentrate in slurryform with dispcrsants for bituminous material, washing the scrubbedslurry free of contaminants and dispersants and aerating and agitatingthe scrubbed concentrate in the absence of a collector to effectflotation and to recover a second bituminous concentrate containing theuranium constituents.

5. A method for the beneficiation of uranium-bearing asphaltite orewhich comprises comminuting the ore to liberation of the bituminousconstituents, converting thc liberated ore to an'aqueous pulp,conditioning the aqucout pulp with frother material, agitating andaerating the pulp in the absence of a collector to effect flotation of abituminous concentrate, scrubbing the concentrate in slurry form withsodium silicate, washing the scrubbed slurry free of contaminants andsodium silicate and act ating and agitating the scrubbed concentrate inthe obsence of a collector to effect flotation `and to recover a secondbituminous concentrate containing the uranium constituents.

6. A method for the benefcation of uranium-bearing asphaltite ore whichcomprises comminuting the ore to liberation of the bituminousconstituents, converting the liberated ore to an aqueous pulp,conditioning the aqueous pulp with frother material, agitating andaerating the pulp inthe absence of a collector to effect flotation of abituminous concentrate, scrubbing the concentrate in slurr;y form withsodium hexametaphosphate, washing the scrubbed slurry free ofcontaminants and sodium and sodium hexametaphosphate and aerating andagitating the scrubbed concentrate in the absence of a collector toeffect flotation and to recover a second bituminous con` centratecontaining the uranium constituents.

7. A method for the beneflcation of uranium-hearing asphaltiteimpregnated limestone which comprises cornminuting the' ore to -a sizesuch that the largest particles fall in the range between about 10 meshand about 20 mesh, converting the comminuted ore to an aqueous pulp,conditioning the aqueous pulp with about 0.04 pound of pine oil per tonof dry solids, agitating and aerating the pulp in the absence of acollector to eect otation of r a bituminous concentrate, scrubbing theconcentrate in slurry form with between about 5 pounds and about 10pounds of sodium hexametaphosphate per ton of dry solids, washing thescrubbed slurry free of contaminants and sodium hexametaphosphate andaerating and agitating the scrubbed concentrate in the absence of a co1-lector to effect otation and to recover a second bituminous concentrate.

8. A method for the benelciation of uranium-bearing asphaltiteimpregnated limestone which comprises comminuting the ore to a size suchthat the largest particles fall in the range between about mesh andabout 20 mesh, converting the comminuted ore to an aqueous pulp,conditioning the aqueous pulp with about 0.07 pound of pine oil per 'tonof dry solids and about 0.6 pound of Bunker C fuel oil per ton of drysolids, agitating and aerating the pulp in the absence of a collector toeffect otation of a bituminous concentrate, scrubbing the concentrate inslurry form with between about 5 pounds and about 10 pounds of sodiumhexametaphosphate per t0n of dry solids, washing the scrubbed slurryfree of contaminants and sodium hexametaphosphate and aerating andagitating the scrubbed concentrate in the absence of a collector toelect otation and to recover a second bituminous concentrate.

9. A method for the beneiiciation of uranium-bearing asphaltiteimpregated limestone which comprises cornminuting the ore to a size suchthat the largest particles fall in the range between about 10 mesh andabout 20 mesh, converting the comminuated ore to an aqueous pulp,conditioning the aqueous pulp with about 0.07 pound per ton of pine oiland about 0.6 pound per ton of Bunker C fuel oil, agitating and aeratingthe pulp in the absence of a collector to effect otation of a bituminousconcentrate, scrubbing the con- References Cited in the le of thispatent UNITED STATES PATENTS 1,454,838 Borcherdt May 8, 1923 2,130,144McClave Sept. 13, 1938 2,161,010 Breerwood June 6, 1939 2,363,315 GrotheNov. 2l, 1944 2,389,727 Herkenhoi Nov. 27, 1945 2,469,422 Weinig May 10,1949 2,507,012 Heilmann May 9, 1950 2,594,929 Howell Apr. 29, 1952 OTHERREFERENCES Denver Equipment Company Handbook, 1954, Denver EquipmentCompany, pages 582-609.

Taggart: Handbook of Mineral Dressing, 1945, pages 12-35.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION A Paten@ Nq,2973e64 I March n i961 l Phillip ,E McGarry vIt is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column lv line 20 for "'imprognated" read am impregnated fm; column lIline 9Y strike out "in the absence of a collector and insert the sameafter vpulpm in line l()U seme column; line 64H strike outl "andsodium"o Signed and sealed this 19th day of September i961' (SEAL)Attest:

ERNEST w. SWIDER f DAVID L. LADD Attesting Officer Commissioner ofPatents USCOMM-DC

1. A METHOD FOR THE BENEFICIATION OF URANIUM-BEARING ASPHALTITE OREWHICH COMPRISES COMMINUTING THE ORE TO LIBERATION OF THE BITUMINOUSCONSTITUENTS, CONVERTING THE LIBERATED ORE TO AN AQUEOUS PULP ANDAGITATING AND AERATING THE PULP IN THE ABSENCE OF A COLLECTOR TO EFFECTFLOTATION OF A BITUMINOUS CONCENTRATE, SCRUBBING THE CONCENTRATE INSLURRY FROM WITH DISPERSANTS FOR BITUMINOUS MATERIAL, WASHING THESCRUBBED SLURRY FREE OF CONTAMINANTS AND DISPERSANTS AND AERATING ANDAGITATING THE SCRUBBED CONCENTRATE IN THE ABSENCE OF A COLLECTOR TOEFFECT FLOTATION AND TO RECOVER A SECOND BITUMINOUS CONCENTRATECONTAINING THE URANIMUM CONSTITUENTS.